Electrical discharge device



March 8 1960 H. GAWEHN 2,928,013

ELECTRICAL DISCHARGE DEVICE Filed Nov. 16, 1955 Inventor J/erberl Gawehn ELECTRICAL DISCHARGE DEVIC Herbert Gawehn, Munich, Germany. afignot S emens & Halske Aktiengesellschaft, Munichand: Berlin, Germany, a German corporation Application November 16,1955, Serial No. 547,247 Claims priority,applicationGermany December 23 1954 16 Claims. (Cl. srs -so) e present nv nt n re ates. to a gas-O v por-fille electrical discharge device operating as; a switching tube or the like and comprising at least one; unheated hollow cathode and electrodes to form in coaction with the cathode a main discharge path and at; least one-auxiliary discharge path. l I Y The use in gasor vapor-filled discharge devices of a hollow cathode is broadly speaking known. The inven{:

tion proposes to provide for the stated purpose a hollow cathodecomprising annular or framelike elements forming an annular cavity extending in the manner of a narrow gap perpendicular to the axis of formed in said elements.

The cathode comprises at least two annular or framelike elements or parts connected together so *as ,toform the opposite ends and inner walls of the cathode, such walls or parts thereof being provided with openings. The indicated parts are shaped so as to form an inner or an outer annular gap or both an inner and outer annular gapmanner be shaped by pressing,.drawing, stamping or the like. They may be fastened to each other along an annular zone by welding, soldering and the like.

The corresponding cathode parts may be shaped so as to form an annular activeinner gap and anouter cooling gap forming wide peripherally extending cooling surfaces. The aperture width of the inner recess or cavity formed may be variously dimensioned by correspondingly dimensioning the size of the front and rear openings provided in the cathode-forming parts. One of an opening or openings the openings may be made particularly small or may be entirely closed or omitted. a

The cathode parts may be made of pure metal or metals, in particular molybdenum, tantalum or the like. Furthermore, the cathode may be'provided', particularly in the active'or working gap, with an emitting substance. The invention" will be explained with reference to .the accompanying drawing showing in diagrammatic simplified representation essential parts of one embodiment thereof. g

In the embodiment shown, the cathode 1 comprises two annular disks 2 and3, forming both the cathode for a main discharge and for an auxiliary discharge.

Thetwo cathode parts may .inknown' cooling, without den'iinemail affecting ashame- I properties-L I i s The cathode is fastened tothe tube wall v by means of a supporting pin 9 which engages the. outer gap.

It is possible to form with proper and suitable. spacingof the individual electrodes an auxiliary discharge bk: tween the cathode and the anode 5, in a suitable circuit supplying voltagecver a sutficientlyv higligseri'es, resi t:x

' ance, which burns. in the region of dark, presparking current, and to produce, by known applicationoi able control voltages, for instance pulse. voltagesor ionization .to the cathode so as. to. excite the m voltage increases of similar action, tovthe. starter elece trode 11, an ignition or at least sufiiciently strong 1 charge along the, path to the. anode 4.

The starter electrode 11 for the main the anode. 5 of the auxiliary discharge, pathare. in the illustrated'embodiment disposed; on opposite? sides of.

the cathode which is thus common. to. these; discharge paths. .The starter electrode 11 need not be arranged between the cathode and main anode 4; it is possible to dispose it so that'it extends from itherear axially symmetrically into the cathode opening in a manner similar. to the anode 5 for the auxiliary discharge path. It is also possible to combine the starter electrode and the anode for the auxiliary discharge path in a single openings of respectively differentsize being formed in The maindischarge occurs on' the left hand side of the may be made by embossing, pressing, drawing and the like, and two openings 6 and 7 formed therein, made of different size. The two disks may be connected together by welding along an annular zone .8. The disks form an inner active or working gap-for the discharges, and

, also a widened outer gap for more efiicient dissipation of heat. The widths and diameter of the outer gap may be made as large as desired, to provide for efiicient electrode.

Circuit details known practice and means; and structural details not Y specifically described may likewise be provided in. accordance with known practice.

Changes may be made within of the appended claims.

I claim; 1. In a gaseous electrical discharge tube, an unheated hollow cathode comprising two disk-shaped parts each having an annular portion rising from the general plane form respectively an inner annular cavity and a periph erally extending annular radially outwardly facing gap, supporting means for said cathode disposed in said gap,

the walls of said parts'defining said inner cavity, a main anode disposed on one side of said cathode spaced therefrom to provide for a main discharge therebetween an auxiliary anode disposed on the other side of said an auxiliary discharge therebetween, a starter electrode terminating relatively close to the opening formed in one of said walls, and circuit connecting means for 'said cathode and anodes and starter electrode respectively.

2. A structure and cooperation of parts according to claim 1, wherein said anodes extend symmetrical to the axis of said cathode.

3. A structure and cooperation-of parts according to claim 2, comprising an emitting substance carried by a leastqone 'of said parts-within. said cavity.

4'. In a gaseous electron discharge device, the com-' bination of a hollow coldcathode .and an anode spaced from said cathode to provide a main discharge path therebetween', said cathode comprising a generally annular hollow disklike member, the axis of which extends along the line of said main discharge, and auxiliary anode means cooperable with said cathode to produce an auxiliary discharge confined to the interior of the latter. Y

5. A discharge device according to claim 4 comprising two annular disk-shaped parts connected together to form said hollow cathode, an openingbeing formed in at least one of "said walls centrally thereof.

6. A discharge device according to claim 4 comprising Patented s, rare.

discharge and may be arranged in accordance with the scope and spirit 3 marginal extensions carried by said disk-shaped parts and forming cooling surfaces for the cathode formed thereby.

7. A discharge device according to claim 4, wherein said cathode 'body is made of molybdenum.

8. A discharge device according to claim 4; wherein said cathode body is made of tantalum.

9. A. discharge device according to claim 4, comprisingan' emitting substance carried by said cathode within the hollow space thereof; U .10. A discharge device according to claim 5, wherein said auxiliary-anode means comprises a second anode extending substantially symmetrical to the axis of said opening.

1 11. A discharge device according to claim 10, comprising means forming a control electrode terminating in thevicinity of said opening. ';.-12;:'A discharge device according to claim"5, wherein said connected cathode parts form a generally annular gap therebetween.

13.lA discharge device according to claim 5, wherein an openingis formed in' each of said walls, said openings being of difierent size.

14. A discharge device according to claim 13, wherein one of said. openings is very small as compared with the other opening.

15. A discharge device according to claim 5, wherein said connected cathode parts form said interior space constituting an annular inner working gap, and marginal extensions carried by said parts forming cooling surfaces defining an outer gap.

16. A discharge device according to claim 12, wherein said cathode parts form generally annularly extending mutually engaging connecting portions which are fastened together.

References Cited in the file of this patent UNITED STATES PATENTS 

